Lamp sealing machine head



0d. 10, 1950 J, E, NELSON ETAL 2,525,043

LAMP SEALING MACHINE HEAD Filed oct. 12, 1944 2 sheets-sheet 1 Oct. l0, 1950 .La NELSON Erm.

LAMP sEALING HCHINE HEAD 2 Sheets-Sheet 2 Filed Oct. 12, 1944 WVM M www; m SEAJMME T. @aaa/HN T mNg/fMMA mfmfq W V M E NSHAUM H JWM/Jw/AT TU HR JAFJWAF Patented Oct. l0, 1950 UNITED STATES PATENT OFFICE LAMP SEALING MACHINE HEAD James E. Nelson, Stephen Bosworth, and William Percy, Toronto, Ontario, Frank Balne, Bronte, Ontario, and Arthur Holman, Toronto, Ontario, Canada, assignors to General Electric Company, a corporation of New York Application October 12, 1944, Serial No. 558,380

` In lCanada December 15, 1943v 3 Claims.

Our invention relates to lamp sealing machines and particularly to machines for sealing doubleended tubular lamps.

In the manufacture of double-ended tubular lamps such as the fluorescent lamps now on the market a preformed mount consisting of an electrode with its lead wires sealed in a glass stem having a flare vof a diameter approximating that of a glass tube to which it is to be sealed, is sealed by fusion in each end of an elongated tube, and a contact carrying base is applied to each end.

In operation the based lamps are detachably mounted between spaced xed contacts and it is therefore important that their overall length be uniform so that they are interchangeable in standard fixtures. It is also desirable that as great a proportion of the space occupied by the lamp be occupied by the luminous tube and as small a proportion as possible occupied by the bases. To this end small flat bases are fitted over the sealed ends of the tube and it is therefore desirable that the seals be uniformly shaped and the overall length of the sealed tube be standard so that the bases may be accurately tted thereto to give the correct overall length of the lam'p.

It is an object of our invention to provide apparatus for the fusing of the flared glass stems supporting electrodes into the ends of the lamp tube in a ready and economical manner at high speed.

Another object of our invention is to provide apparatus for sealing the glass Vstems to the bulbs so that the sealed portions are properly shaped and dimensioned so that bases may be attached ther-etc to give the desired overall length of lamp.

Another object of our invention is to provide a sealing head which may be easily loaded and unloaded by the operator, which rmly holds the lamp in position during shaping operation on the seal, and which is adapted to form uniform seals from commercial stems and bulbs which may vary slightly in form from one another.

Other objects and advantages will appear from the following detailed description with accompanying drawings of a specic form of our invention. In the drawings Fig. 1 is a plan view, partially broken away, of a sealing machine embodying my invention; Fig. 2 is a vvertical section on a larger scale than Fig. 1 through one of the heads of the machine with parts in position to be sealed; Fig, 3 is a fragmentary vertical section of the head of the supporting spindle; Figs. 4, 5 and 6 are detailed views of parts of the mechanism; and Figs. 7, 8 and 9 are views of the bulb gripping portion of a sealing head.

The apparatus shown in Fig. 1 comprises sixteen heads l I equally spaced about the periphery of the turret I2 and rotatively mounted therein. The turret I2 is indexed to move intermittently in a counterclockwise direction in a manner well known in lamp sealing machines, so that each head occupies successively for a predetermined period each of the sixteen work stations indicated by the letters A to Q. The rotation of the heads is accomplished by a belt drive. A belt 6U is driven continuously by a mechanism generally indicated at 6I and which may derive its power from the main drive of the lamp machine. The belt t!) engages grooved pulleys I4 (shown in Fig. 2) at the bottoml of the heads. All the heads except those located at stations A and B are engaged by the belt and consequently all the heads ar-e continuously rotated individually during operation of the machine except when they are at stations A and B where they are disengaged from the belt 60 and when they are at stations J and K where mechanism is provided to hold them against rotation.

The vgeneral sequence of operation of the machine will now be described. An operator is stationed opposite stations A and B and a second operator is stationed opposite stations J and K. These are the loading and unloading stations where the heads are not rotating. At station B the operator places a ared mount which is similar. to the mount 5l shown in Fig. 3 except that the exhaust tube is absent, in the head then at the station, and then places on the ared mount a glass lamp tube 50 which assumes a position with respect thereto as shown in Fig` 2. The tube 50 is firmly held in this position by a suction holder Z3 engaging the side Wall of the tube. At the next station C the parts are preheated by suitable res such as shown at 52 opposite station C. At stations D, E, F and G hard sealing fires 53 such as diagrammatically shown in Fig. l opposite these stations are directed at the seals. At the three sealing positions E, F and G suitable mechanism to be later described operates on the seal to shape and locate it. Station I-I is an annealing position where suitable res diagrammatically shown at 5'! are applied to give a controlled rate of cooling. At station J rotation of the sealing head is stopped in a predetermined position conve-nient for the operator by mechanism indicated at 59 which holds it against rotation while the head occupies both stations J and K. The operator opposite stations J and K removes the lamp tube 50 with the mount sealed thereto, places a ared mount 5l, such aS Shown in Fig. 3 with the exhaust tube 65, in

the head, reverses the lamp tube and places it in the holder 23 with its open end in sealing relation to the nare l, as shown in Fig. 2. The head is then stepped through a series of positions L to Q which the same series of operations performed at stations C to H and are carried out to seal this end of the tube. L is a preheating station similar to station C and at stations M, N, O, P the seal is completed in the same manner as at stations D, E, F and G. Station Q is an annealing station similar to station H. At stations A and B the heads encounter a mechanism 59 which is a duplicate of mechanism 59 at stations J and K, whereby rotation of the head is stopped in a predetermined position to facilitate loading and unloading. The completely sealed lamp is removed at station A and the head is ready for reloading.

Referring particularly to Fig. 2 for a description of the sealing head, each head II has a sleeve I3 rotatively mounted in va bearing @il in the turret I2. The sleeve I3 carries at its lower end a grooved driving sheave Id. A spindle having a mount pin I9 with an enlargement or head at its upper end is mounted axially of the head in a manner whereby it rotates with the head but can be moved longitudinally during rotation. This spindle comprises three parts, a rod I5 extending axially of the sleeve I3, a hollow section I8 having its lower end detachably tted in a socket II at the upper end of the rod I5, and an upper section constituting a mount pin I9 having the enlargement or head 29. The upper surface of the mid-portion of the pin head 20 is of conical shape approximately conforming to the shape of the nare portion of mount 5 I. The lower end of the socket part I1 of rod I5 rests on the upper surface of the head II thereby defining the downward limit of movement of the rod and consequently the vertical position of the flare mount pin head 28. The lower end oi the rod I5 carries an enlargement IS constituting a tappet to be engaged by mechanism (to be later described) for the purpose oi raising the spindle. The pin I9 is proportioned to loosely nt in the section I8 and its enlargement or head 29 is hollow, and so shaped that the exhaust stem 65 and the lead wires 9S may be loosely accommodated therein to permit the flared mount 5I to rest on the support with some amount of lateral adjustment thereon. Projecting upwardly from a boss 2| on the head i i is a hollow support rod 22 carrying at its upper end a lamp holder 23 equipped with a valve 33. A passageway 25 drilled in the boss ZI establishes communication between the bore of support rod 22 and the annular space 26 between the rod I5 and the central part of the sleeve I3 which is of enlarged internal diameter at this point. An opening 2 in the sleeve I3 establishes communication with an annular chamber 28 provided in the bearing 3d.

Connection of the chamber 28 with an exhaust system is made by means of a pipe 29. It will be apparent from the construction just described that communication between the hollow stem 22 and the pipe 29 exists during rotation of the head I I in its bearing.

The construction of the suction holder 23 will be best seen by reference to Figs. '7, 8, and 9. The holder 23 carries a gripping portion 39 having the shape of a longitudinal section of a cylinder of the same diameter as the tubular bulb to be held. A rubber gasket 3| surrounds the edge of the forward face oi the grip 39 dening a ysuction chamber 32. A cylindrical` slide valve 311 having operating buttons 35 and 36, one at each end, is arranged to be reciprocated in a cylindrical bore 82 extending transversely of the holder 23, its movement being guided andlimited by a stop pin 3'! thereon engaging in a groove 33 in the holder. interconnected passageways are provided in the slide valve 34 and in the holder 23 in a well-known manner at positions such that when the slide 3l. is moved to the position shown in Figs. 7 and 9 and also in Fig. 2, the chamber 32 is in communication with the hollow support 22 and consequently with the exhaust system. When the slide valve 33 is moved to its other extreme position illustrated by Fig. 8 the exhaust system is closed off from the chamber 32 and communication is established between the chamber 32 and the atmosphere. To this end the valve 34 is provided with a rightvangle passage 36 (Fig. 2) which, when the valve is in the position shown in Figs. 2, 7 and 9, joins the passages 8l, S8 (Fig. 2) in the holder 23, thereby connecting the chamber 32 with the interior of support 22 and thence through opening 89 in support 22 with passage 25 in boss 2|, passage 99 in head Il, aperture SI in sleeve I3, annular space 26, opening 2, annular chamber 28 and pipe 29.

To load a head I I the operator places a flared mount 5I on the mount support 29 in the position shown in Fig. 3. The lamp tube 59 is then placed with its end engaging the flare 5I as shown in Fig. 3 and the body of the tube is pressed against the gasket 3|. The operator may use a finger of the hand pressing the tube in position on holder 23 to engage the button 35 and push the slide valve 34 to the position indicated in Fig. 9 whereby connection to the exhaust system is made and the tube is rmly held by suction in the desired position. The loose fit of the mount 5I on the support 29 permits a self alignment of the parts to be sealed and permits the proper relative location of the parts 59 and 5I to be sealed regardless of slight discrepancies in the size of the parts such as'eccentricity of the tube 50.

The holding apparatus described permits easy and quick assembly of the tube 59 in a definite position on the head II by the operator who places it against the holder 23 with one hand and operates the valve to secure it in position by suction, with a finger of the same hand. The tube 59 is rmly held so that it retains its original position during subsequent operations on its lower end during sealing as will be later described. Similarly the sealed tube may be readily unloaded by the operator with one hand by grasping the tube opposite the holder 23 in such a manner that a nger engages the button 36 of the valve 3H to slide it to the position where connection with the exhaust is broken and the lamp released. Further the support 2U as described permits some latitude of movement of the flare 5I thereon whereby the flare is self-adjusting to centre with the end of the tube in sealing position in such a manner that it accommodates the parts with considerable tolerance of size and shape of the parts such as is encountered in their commercial manufacture at high speed.

When the head moves from position B it is released from holding mechanism 59 and its driving sheave Ill comes into engagement with the belt 69 which causes it to rotate. At position C the glass parts are subjected to suitable fires indicated at 52 whereby their temperature is raised towards the fusing point, At position D harder res are concentrated at-the seal to raise them't a'temperature approaching fusion. 'At stationfE the seal is fused by further sealing res 53.fIn this position mechanism generally indicated at 55 in Fig. 1 and shown in detail in Fig. 4 engages beneath the tappet I6 of the reciprocable spindle I5. This mechanism consists of an arm 4I pivoted at 42 in a bracket Yfili mounted on stationary base plate `4I) of the machine. One end of the arm carries the counterweight 43 and the other end a roller 44 which is pressed against the tappet I6 by the counterweight. An adjustable stop 45 bears against the bracket 46 and determines the upper limit of movementof the roller M. As the meeting edges of the nare 5I and the bulb 56 become fused they are pressed upwardly a distance determined by the setting of the stop 45 and are tacked together to form a seal, the bulb 50 being rmly held by the suction grip 23. When the head moves from the positionE it clears the mechanism 55 and the spindle drops to its normalposition. In this position the seal is spaced from the support 26, and the sealing hres at the next position F can unobstructedlyfimpinge on it, and heat is notrabstracted from the fused parts by conduction through the metal support.

`The seal further fused at station F tends to sag somewhat from the position to which it was elevated at station E by mechanism 55. Immediately after the head leaves station F in its `travel towards station G it encounters mechanism 56 shown in detail in Fig. 5 whereby the spindle is bumped up a predetermined amount. The mechanism 56 consists of a roller 'I6 mounted on a bracket 'II secured to the stationary plate 40 in the path of movement of the tappet I 6. The engagement of the tappet I 6 by the roller I6 bumps up the spindle and consequently presses upwardly on the seal. When the head has passed the mechanism 55 the spindle drops to its normal position whereby it is spaced from the seal and the sealing res 53 at the next station G are most effectively employed as described in connection with station F. When the head leaves station G it engages mechanism 'I6 shown in dotted lines in Fig. 1 and in detail on an enlarged scale in Fig. 6. This mechanism consists of a track 'I6 supported a predetermined distance above the base plate in the path of movement of the tappet I 6.

As theV tappet I6 rides up the beveled end 'I4 of track 16 the spindle is elevated to press upwardly on the seal and is maintained in this elevated position during its travel to the next station H. This is an annealing station where the rate of cooling of the seal is controlled by suitable res indicated at 51. The supporting track 16 to support the seal is provided at this point for the reason that the flare sealed in the tube as described is loosely positioned in the support 26 and the lead wires accommodated in its central bore. The lead Wires are somewhat resilient and if the 6 tation of the head is stopped in a position which is most convenient for the operator in unloading and to hold it in this position against rotation so that it may be conveniently loaded. This mechanism is best shown in Fig. l and comprises a' spring bar 'I5 pivoted at I6 on a bracket Il secured to-the stationary base plate 40 of the machine. The free end of the spring bar is engaged Y by a dog 'I8 rotatively supported on the base softened glass of the seal as finally formed at Y station G'and by cam surface 14, is not supported until the seal has time to harden somewhat they are liable to tip the nare with the result that a distorted seal is formed.

It has been described that at the station E and on leaving the stations F and G the glass as softened at these stations is pressed upwardly a predetermined amount to bring the seal to form. It is preferable that the height to which the seal is pressed should be slightly greater successively at these stations.

When the head moves from the annealing position H, mechanism 59 is provided whereby rohead-is stopped. As the pin BI is secured on the pulley I4 in predetermined relation to the position of the vsuction holder 23 the rotation is stopped with the holder 23 lying in the most advantageous position to permit unloading of the lamp with the rst seal complete and the reloading of the head. As the head travels from stationV J to station K it is held against rotation by the belt by reason of the fact that the pin 8! `slides along the bar 'I5 which is sufficiently resilient toY permit this movement. If it should happen that the pin 8l was in a position such that it engages the bar I5 head on when it rst makes contact, the spring biased dog IS will 'given to an amount sufficient to permit the head to continue its ro-l tation and to be stopped in the desired position when the pin next engages the bar.

At station J the tube 5U with the seal completed at one end is removed by the operator. At station K a nared mount 5I such as shown in Fig. 3 with exhaust tube 65 is placed in the head 20, the tube is inverted and its end 63 placed on the flare in the same manner as described for loading at station B. The stations L to Q inclusive correspond to the stations C to H whereby the seal at the other end of lamp is completed and delivered to unloading station A. To this end a duplicate (not shown) of mechanism is provided at station N, and station O is provided with mechanism 56 which is a duplicate of mechanism 56 at station F. Also, a preheat burner 52 is located at station L, fusing burners 53 at stations M, N, O, P, and an annealing burner 57 at station Q. In this case, however, the mechanism for raising the spindle head as it leaves the last sealing fires P is illustrated as mechanism 56 similar to mechanism 56 and 56 used at stations F and O. As the are mount for sealing the second end of the tube has the exhaust vtube extending well down into the bore of the spindle I 9 the flare is supported by it against tipping in the manner described with respect to station H, and the support mechanism of Fig. 6 used between stations G and H is, therefore not required between stations P and Q, though it may be used if desired.

The apparatus described permits easy and rapid loading of the parts in the heads and is adapted for high speed operation. The arrangement provided for fusing and uniting the parts and working the seal to its nnal form results in uniformly shaped and positioned seals, so that overall length of sealed lamps is uniform and so that the bases may be readily and uniformly applied to give uniform length of completed lamp.

While we have shown and described a preferred embodiment of our invention, it will be obvious to those skilled in the art that various substitutions, modifications or omissions may be made therein without departing from the spirit of our invention.

What we claim as new and desire to secure by Letters Patent of the United States is:

1. Apparatus for sealing mounts in elongated lamp tubes comprising a sealing head having a mount supporting spindle, a standard projecting upward from the head and carrying a suction chamber shaped to engage the side of the lamp tube, a passageway leading from said suction chamber through the head to an exhaust system, a Valve in said passageway adjacent the suction chamber.

2. Apparatus for sealing mounts in elongated lamp tubes comprising a sealing head having a mount supporting spindle, a standard projecting upward from the head and carrying a suction chamber shaped to engage the side of the lamp tube, a passageway leading from said suction chamber through the head to an exhaust system, a reciprocable valve in said passageway adjacent the suction chamber, said valve constructed and arranged to be engageable by the fingers of the hand of an operator holding a lamp tube on said suction chamber.

3, Apparatus for sealing mounts in elongated lamp tubes comprising a sealing head having a mount supporting spindle, a standard projecting upward from the head and carrying a suction chamber shaped to engage the side of the lamp chamber through the head to an exhaust system, a reciprocable valve in said passageway, said valve located immediately in the rear of the suction chamber and lying transverse thereto whereby it is readily engaged by the fingers of a hand applying a tube to the suction chamber.

JAMES E. NELSON.

STEPHEN BOSWORTH.

WILLIAM PERCY.

FRANK BALNE.

ARTHUR HOLMAN.

REFERENCES CITED The following references are of record in the le of this patent:

UNITED STATES PATENTS Number Name Date 1,475,192 Marshall Nov. 27, 1923 1,655,050 Eisler Jan. 3, 1928 1,924,532 Zimber et al Aug. 29, 1933 2,063,235 Esler Dec. 8, 1936 2,143,708 Muller et a1 Jan, 10, 1939 2,153,370 Donovan et al Apr. 4, 1939 2,237,186 Malloy Apr. 1, 1941 2,268,510 Kluberg let al. Dec. 30, 1941 2,335,617 Thomas et al. Nov. 30, 1943 2,349,822 Gardner May 30, 1944 2,434,664 Malloy Jan. 20, 1943 

